A 0.7cm2 3.5GHz, -31 dBm Sensitivity Batteryless 5G Energy Harvester Backscattering Chip for Asset Identification in IoT-Enabled Warehouses

The IoT's expansion calls for ultra-low power wireless systems. With 6G on the horizon, wireless energy harvesting backscatter paves the way for improved energy efficiency and enhanced connectivity, without conventional batteries and high-power radios. Despite licensed spectrum scarcity, the telecom industry explores deploying backscattering technology in licensed bands due to higher transmitter power and advanced interference management [1]. Past research on RF energy harvesters emphasized enhancing the rectifier sensitivity for heavily duty-cycled applications but lacked the ultra-low power backscattering circuits [2]–[4]. Others [5], [6] have advanced backscattering technology but sacrificed sensitivity and active communication power
$(\approx 10-30\mu\mathrm{W})$
, burdening the wake-up charging time at low
$(< -30\text{dBm})$
available power levels. This is especially critical in IoT-enabled warehouses where swift inventory counting is essential (Fig. 1 top) with broad coverage. Furthermore, the form factor should be minimized to validate the batteryless harvesters. The pursuit, therefore, continues to design a comprehensive system running at higher 5G frequencies (hence lower form-factor) that combines high sensitivity, simple backscattering communication and thus, low start-up times.